(Adds details from court ruling, comment from Massachusetts attorney general)
BOSTON, April 13 (Reuters) - Massachusetts' top court on Friday rejected Exxon Mobil Corp's bid to block the state's attorney general from obtaining records to investigate whether the company for decades concealed its knowledge of the role fossil fuels play in climate change.
The Massachusetts Supreme Judicial Court ruled Attorney General Maura Healey had jurisdiction to seek records to probe whether the oil company's marketing or sale of fossil fuel products violated the state's consumer protection law.
The ruling marked another setback for Exxon after a federal judge in March dismissed a related lawsuit it filed seeking to block investigations by Healey and New York Attorney General Eric Schneiderman.
Exxon argued that as a corporation incorporated in Texas and New Jersey, Healey had no basis to issue a demand for documents in 2016 to conduct a Massachusetts-based investigation of whether the oil company misled consumers and investors.
But Justice Elspeth Cypher, writing for a 6-0 court, said jurisdiction existed because of Exxon's control over advertising conducted for more than 300 franchise gas stations operating under the Exxon and Mobil brands in the state.
She said Healey's probe related to how manmade greenhouse gas emissions had caused climate change, "a distinctly modern threat that grows more serious with time, and the effects of which are already being felt in Massachusetts."
Healey in a statement declared victory and said Exxon must come forward with the truth about what it knew about climate change and when it knew it.
"The people of Massachusetts - and people everywhere - deserve answers," she said.
Exxon did not immediately respond to a request for comment.
Healey and Schneiderman launched their investigations following news reports in 2015 saying Exxon's own scientists determined that fossil fuel combustion must be reduced to mitigate the impact of climate change.
Those reports by InsideClimate News and the Los Angeles Times were based on documents from the 1970s and 1980s. Exxon contended that the documents were not inconsistent with its public positions.
Exxon has said the investigations were politically motivated. It filed a lawsuit challenging Healey's records request and filed another case in federal court challenging the probes by her and Schneiderman. (Reporting by Nate Raymond in Boston Editing by David Gregorio and Bill Trott)